I've flashed JB to my TL via Spectre51's FTF. I previously had a generic Xperia T JB .489 on it prior. I excluded data during the flash to keep all the apps and settings intact.
The animation speed in the launcher is also faster, e.g. it takes less time for each transition to complete when swiping homescreens. This is an improvement to me since I think the generic Xperia JB homescreen swipe animation is too slow. The app drawer animation appears be unchanged.
The Xperia weather widget also doesn't cause lag like in the generic. :good:
Being this is an AT&T firmware, manual selection of networks is absent but apps such as LTE Setting still work.
Homescreen and app drawer position dots are both at the bottom of the screen as was the case with ICS.
The Skyfall theme is gone but the 3 Skyfall wallpapers are present as well as the Ringtone and Notification sound.
All the usual bloatware is present along with a new one called AT&T DriveMode. And there are some minor changes to the stock Android browser such as a new tabs graphic that shows a number to indicate opened tabs and back/forward buttons in the navbar.
The Smallapps bar in Recent Apps is dark again like in ICS. I think it looks better this way.
Auto brightness is working at the time of this post.
I haven't yet tested the Walkman to see if it still stalls when the phone is locked...
So far I'm digging this firmware. The phone feels smoother and faster.